CN1848671B - Variable-gain differential amplifier - Google Patents
Variable-gain differential amplifier Download PDFInfo
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- CN1848671B CN1848671B CN2006100673149A CN200610067314A CN1848671B CN 1848671 B CN1848671 B CN 1848671B CN 2006100673149 A CN2006100673149 A CN 2006100673149A CN 200610067314 A CN200610067314 A CN 200610067314A CN 1848671 B CN1848671 B CN 1848671B
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- 239000003990 capacitor Substances 0.000 description 3
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- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- 230000003321 amplification Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
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- 238000004519 manufacturing process Methods 0.000 description 2
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- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
- H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
- H03F3/45475—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using IC blocks as the active amplifying circuit
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Abstract
A variable-gain amplifier with high input impedance includes positive and negative inputs, positive and negative outputs, first and second differential circuits and first, second and third impedances. The impedances form an impedance bridge between the outputs. The first and second differential circuits each have one input coupled to one of the inputs of the differential amplifier, one input coupled to the impedance bridge, and two outputs connected to the outputs of the differential amplifier. At least one of the impedances is a variable impedance.
Description
Technical field
The present invention relates to integrated amplifier, relate more specifically to have the differential amplifier of the gain controlling input that is used to regulate amplification ratio.
Background technology
This variable gain amplifier is used under automatic gain control (AGC) amplifying circuit, particularly audio applications significantly.
In the variable gain amplifier of multiple known type, all amplifiers use many to being called as the signal of differential signal.Differential signal allows to improve signal to noise ratio and makes it possess the ability of the higher frequency of being operated in.This amplifier can be used for for example data communication system.
Basically, two kinds of technology are used in the design of variable gain amplifier.First kind of technology is that the negative feedback device of amplifier is changed.Second kind of technology is for example on the books in document WO 2002/49210, and it has increased the variable attenuation level in the input of amplifier.No matter which kind of technology of use, a shortcoming of known circuit is to show low input impedance (the 10k Ω order of magnitude).
Summary of the invention
The present invention proposes a kind of variable gain amplifier with high input impedance (1M Ω order of magnitude).Usefully, the amplifier that is proposed can form with simple relatively method manufacturing with known ic manufacturing technology.
For this purpose, a first aspect of the present invention proposes a kind of differential amplifier and has first input, second input, first output and second output.This amplifier comprises first difference channel and second difference channel.First difference channel has: first input that is coupled in differential amplifier first input; Second input; And may be coupled in first output of differential amplifier and first output and second output of second output respectively via amplifying circuit such as the 3rd difference channel.Second difference channel has: first input that is coupled in differential amplifier second input; Second input; And first output and second output that are coupled in differential amplifier second output and first output respectively.Differential amplifier also comprises: first impedance that differential amplifier first output is connected in second input of first difference channel; Second output of differential amplifier is connected in second input, second impedance of second difference channel; And the 3rd impedance that second input of second differential amplifier is connected in second input of first difference channel.In first, second and the 3rd impedance at least one is variableimpedance.In addition, first and second of first and second difference channels inputs are separately corresponding to each grid of the differential pair of the transistor (for example mosfet transistor) of these circuit.
So connect, these three impedances form the dividing potential drop electric bridge between differential amplifier output, and their are exported (for example shared node of two impedances) and feed back to the input of first and second difference channels, so that variable negative feedback to be provided.Because the input of difference channel corresponding to the MOS transistor grid that is capacitive substantially, therefore can obtain high input impedance.More particularly, can replace MOS transistor to obtain high input impedance by any active device, be to use other type of transistor comparatively significantly, for example MESFET, GaAs transistor or bipolar transistor (BJT) are perhaps with conventional arrangement (before the level of back) or use Darlington configuration etc.
In one embodiment, differential amplifier also comprises: first at least one amplifying circuit of importing with second output of first output that is coupled in first difference channel and second difference channel; Be coupled in second input of second output of first difference channel and first output of second difference channel; Be coupled in first output of differential amplifier first output; And second output that is coupled in differential amplifier second output.This circuit provides high open-loop gain and bandwidth is increased.It also allows the Amplifier Gain of feedback controlled to become more to be independent of the gain of first and second difference channels.
In one embodiment, it is two variableimpedances that degenerative first and second impedances are provided, and the 3rd impedance is a blocked impedance.In actual applications, it is variable only requiring one in first and second impedances, but they all are arranged to the variable symmetry that design and amplifier work then are provided.Under the situation of difference controlled system, this symmetry is favourable.
Usefully, these impedances are to make roughly to be resistive device more easily.
Especially, variableimpedance comprises the element switching array that roughly is resistive, and the value of variableimpedance is controlled to be the function of switching signal, and this function definition comprises the configuration of switching array of one group of resistance element of parallel connection and/or series connection.
In one embodiment, differential amplifier comprises extraly and is parallel to two stabilizing circuits with amplifying circuit, for one of them, second output of first difference channel and first output and second difference channel is connected in second output of differential amplifier, and for another, second output of first difference channel and first output of second difference channel are connected in first output of differential amplifier.These circuit can improve the stability of the amplifier of feedback controlled.
For example, each stabilizing circuit comprises a plurality of impedances that are connected in parallel to each other along separate routes, and each impedance comprises a commutation circuit along separate routes, is used as the control signal function ground disconnection that puts on described commutation circuit input respectively or at least one in the closed described shunt.
When difference channel comprised the current source that makes their output bias, differential amplifier also comprised and is connected in differential amplifier output controlling the compensating circuit of described current source, thus any possible variation in the compensation common-mode voltage.
For example, sort circuit can comprise: connect the resistor bridge of differential amplifier output, this resistor bridge has output node, and this output node transmission is substantially equal to the equal voltage of voltage average of described output place; And error amplifier, it amplifies the voltage difference between described average voltage and the reference voltage, and the error signal of amplifying is passed to current source as control signal.
Another aspect of the present invention relates to audio frequency CD (mini disk) and/or DVD (digital versatile disc) player and/or register, the audio frequency and/or the video decoder unit that relate to " set-top box " type that is used to receive the satellite relay signal, relate to DVB-T (broadcasting of digital video continental rise) type or DVB type encoder and/or the decoder that is used for digital television signal (continental rise or other) or be used for digital multimedia signal (encode sound, image and data) DMB (DMB) type, and relate to audio frequency and/or video tuner (for example TV tuner), comprise differential amplifier according to first aspect.
Description of drawings
Reading to the following describes in conjunction with the drawings can be understood the present invention better, and other features and advantages of the present invention will become more obvious, in the drawings:
Fig. 1 is the functional circuit figure according to amplifier of the present invention;
Fig. 2 illustrates the specific embodiment of presentation graphs 1 circuit;
Fig. 3 illustrates the exemplary embodiment of variableimpedance;
Fig. 4 is the circuit diagram that adds compensation arrangement in amplifier shown in Figure 2 extraly; And
Fig. 5 illustrates the preferable example embodiment of this compensating circuit.
Embodiment
Fig. 1 is the functional circuit figure according to the exemplary embodiment of differential amplifier of the present invention.This amplifier comprises through part by forming impedance 40,50 and 60 coupled to each other together the differential amplifier circuits 10,20 and 30 of feedback loop with ride gain.
The working condition of circuit is as follows.Suppose owing to disturbing the current potential at output S+ place to be raise, this will make the current potential at the input INn10 place of circuit 10 raise.Therefore, its difference input voltage (between input INp10 and INn10) descends.The current potential at the output OUTp10 place of circuit 10 also descends.Follow and descend, and therefore this also occurs on the current potential at output S+ place by the difference input voltage of circuit 30 (between input INp30 and INn30).Such reasoning is represented to feed back and is born.Identical reasoning can be applied on the circuit 20.
As can be seen from the figure, feedback control loop provides negative feedback for a long time.
Yet, beneficially provide amplifying circuit 30 to increase amplifier turn off gain and thus when its feedback control loop be during via impedance 40,50 and 60, Amplifier Gain is shown be independent of the gain of difference channel 10,20.
When open-loop gain is very high, can calculate the Amplifier Gain among Fig. 1 easily, and by following formulate:
In order to make gain-variable and may command, make in all impedances at least one variable just enough.Usefully, impedance 50 is a variableimpedance for fixing impedance 40,60, because symmetry makes layout more simple and clear.Yet, also variableimpedance 50 can be fixed with resistance value or variable impedance 40,60 is used in combination.
The detailed expression of the integrated circuit form of the embodiment of amplifier as shown in Figure 2 among Fig. 1.
For Optimizing operation, can mate right form provides element: current source 120,210 is usefully mutually the same, and transistor 11,12,21,22 has identical size and is provided with close to each otherly.Common current source 13,23 is mutually the same and independent current source 120,210 transmits and common current source 13,23 electric currents that transmitted electric currents about equally.
The positive output of the negative output of difference channel 10 and difference channel 20 is corresponding to the node between independent current source 120 and transistor 11,21 drain electrodes.Similarly, the negative output of the positive output of difference channel 10 and difference channel 20 is corresponding to the node between the drain electrode of independent current source 210 and transistor 12,22.
The positive input of difference channel 10,20 and negative input are corresponding to the transistorized grid of the nMOS that presents high input impedance.Terminal corresponding to the amplifier of these inputs also presents high input impedance.
Here, amplifying circuit 30 is designed to a kind of form: promptly be series at two independent signal amplifiers that current source 33 between two power conductors or 34 pMOS transistor 31 or 32 form by its raceway groove respectively.The input of amplifying circuit 30 is corresponding to the grid of pMOS transistor 31 and 32, and the output of amplifying circuit 30 is corresponding to the drain electrode of pMOS transistor 31,32 and the node between the current source 33,34.
Here, impedance 50 is the blocked impedances that are divided into two resistors 51,52 with similar resistance of series connection.Node A between the resistor 51,52 is the node corresponding to the fixed potential place of common mode current potential.Impedance the 40, the 60th, variableimpedance.
Become in the example at one, resistor the 51, the 52nd, variable and impedance the 40, the 60th is fixed.
Fig. 3 illustrates relevant with blocked impedance 51 or 52 a respectively variableimpedance 40 or an embodiment of 60.In order to realize accurate R2/R1 ratio, under the variation slope of element impedance value can be considered to constant occasion, require to use resistance element with identical value.To selected yield value, for example 20dB, 16dB, 12dB, 8dB and 4dB more are by being made up the impedance that changes corresponding to impedance R2 corresponding to the resistor in series and the parallel connection of R1 value in practice.Therefore, example shown in Figure 3 comprises the shunt of five parallel connections, comprises respectively:
The array of four resistor R 1 of-parallel connection, this array is connected with the array of three resistor R 1 of parallel connection;
-the resistor R 1 of connecting with the array that in parallel two resistor R 1 form;
Three resistor R 1 of-series connection;
The resistor R 1 of-five series connection, they are connected with the array that three resistor R 1 of parallel connection form;
-nine parallel resistor device R1.
For yield value there being other selection, beneficially change corresponds respectively to 51 or 52 impedance.
Here exist many possibilities to change resistance value by switch.Embodiment comprises from a plurality of shunt corresponding to the quantity (being 5 here) of possible yield value and selects No. one resistor.Each along separate routes is connected in Node B+or B-via transistor 101-105, and transistor 101-105 receives the control signal Ci corresponding to selected gain, and i is 1-5 in the example here.At any given time, wherein have only a control signal Ci to work, thereby only select a shunt.
In order to limit variableimpedance shared surface area on silicon chip, resistor is shared to some shunt.
Table 1 hereinafter illustrates the accuracy that can obtain gain with this method, does not comprise the deviation that is associated with device value.
Table 1
As those skilled in that art can notice, the grid-source voltage of transistor 101-105 corresponding to control signal and Node B+or B-between potential difference.Node B+or the voltage of B-corresponding to common-mode voltage, on common-mode voltage, increase the corresponding variable componenent of signal with input E+ or E-to be amplified.When control signal was not had an effect, on the level near low suppling voltage, corresponding crystal pipe 101-105 was cut off.When control signal is done the time spent, near on the level of high supply power voltage, corresponding crystal pipe 101-105 conducting but grid-source voltage is regulated by input signal.The adjusting of gate-to-source signal causes the adjusting to the conductivity of transistor channel, and this adjusting has the effect that the value of impedance R2 is adjusted to the function of input signal.
Owing at least two reasons, the adjusting of impedance R2 can not have problems.First reason is that this adjusting remains under the very weak situation.In fact, this regulated quantity raceway groove resistance and this raceway groove resistance of being used for regulating MOS transistor 101-105 is selected as can ignoring for R1.Therefore formed adjusting also is insignificant.Second reason is that amplifier comprises that two impedance R2 and this two impedance R2 through regulating are conditioned with anti-phase form.If these voltages are considered to be difference, the anti-phase modulation of these phase places compensates one another, and they are equivalent to the common-mode voltage on output S+, the S-is regulated.In fact, according to the application scenario, common-mode voltage can be important also can be unessential.
If because the size of transistor 101-105 is determined and the restriction of the strictness on the common-mode voltage of output, then be necessary to compensate this defective, can add common mode as illustrated in fig. 4 and detect and feedback control circuit 200.
Circuit among Fig. 4 is corresponding to the circuit among Fig. 2, and wherein independent current source 120,210 is replaced with adjustable current source 121 and 211.Circuit 200 is measured the common-mode voltage at output S+ and S-place and is adjusted the constancy of the electric current of adjustable current source 121,211 with the common-mode voltage of assurance differential amplifier output.
By illustration, circuit 200 comprises 201,202 and error amplifiers 203 of two resistors.Resistor 201 and 202 has identical resistance value R and is connected between output S+ and the S-.204 of nodes between two resistance values 201 and 202 are positioned at the common mode current potential place of output.Error amplifier 203 is connected to node 204 and the circuit of the reference voltage V ref that equals to export the common-mode voltage that the place requires is provided.Potential difference between error amplifier 203 amplification nodes 204 and the voltage Vref is to send control signal to adjustable current source 121,211.
In the amplifier that uses feedback loop, exist unsettled danger takes place.This can proofread and correct by stabilizing circuit, and this stabilizing circuit affords redress based on the Miller effect.Stabilizing circuit 300 can be arranged between the input and output of amplifying circuit 30.Yet a shortcoming of these stabilizing circuits is bandwidth that they have reduced amplifier.In fact, in variable gain amplifier, use traditional stabilizing circuit to have the effect that changes the amplifier cut-off frequency according to selected gain.If change in gain is very big, the variation of bandwidth also clearly, this will have problems.
Significantly change for fear of bandwidth, propose to use the stabilizing circuit 300 of an embodiment who describes in detail among Fig. 5 here.In these circuit one the output OUTn20 with the output OUTp10 of differential amplifier circuit 10 and differential amplifier circuit 20 is connected in the output E-of differential amplifier.Another stabilizing circuit 200 is connected in the second output OUTp20 that exports OUTn10 and differential amplifier circuit 20 of differential amplifier circuit 10 the output E+ of differential amplifier.
Compensating circuit 300 comprises the some shunt that are connected in parallel to each other.Each comprises respectively and capacitor C along separate routes
A, C
B, C
CThe resistor R of series connection
A, R
BOr R
C, and the transistor T that forms switch respectively
A, T
B, T
CIn each shunt, resistor is set between transistor and the capacitor.Usefully, each transistor along separate routes is set at the input of circuit 30.And capacitor is set at the output of circuit 30.
Because the variation of amplifier bandwidth can remain in certain tolerance limit, so this stabilizing circuit need not to comprise the quantity that resembles the so much possible yield value of shunt quantity.Each transistor T
A, T
B, T
CReceive control signal M respectively
A, M
BOr M
CAt any given time, have only one in all control signals and have an effect, only a shunt is connected between the input and output of amplifying circuit 30 effectively thus.
As an example, this stabilizing circuit only comprises three shunt to five possible yield values.If control signal C1 or C2 have an effect, signal M then
AHave an effect, if control signal C3 or C4 have an effect, signal M then
BHave an effect, and if control signal C5 has an effect, signal M then
CHave an effect.Under the situation of the possible yield value that has greater number, for example 20 gains, owing to select along separate routes corresponding to three or four yield values, therefore can be with the shunt quantity in the lower ratio increase stabilizing circuit.
Claims (14)
1. have the differential amplifier of first input (E+), second input (E-), first output (S+) and second output (S-), comprising:
First difference channel (10) has: first input (INp10) that is coupled in differential amplifier first input; Be connected in second input (INn10) of differential amplifier first output via first impedance (40); And first output (OUTp10) and second output (OUTn10) that are coupled in differential amplifier first output and second output respectively;
Second difference channel (20) has: first input (INp20) that is coupled in second input of differential amplifier; Be connected in second input (INn20) of differential amplifier second output via second impedance (60); And first output (OUTp20) and second output (OUTn20) that are coupled in differential amplifier second output and first output respectively; And
Second input of second difference channel (20) is connected in the 3rd impedance (50) of second input of first difference channel (10);
Wherein at least one in first, second and the 3rd impedance is variableimpedance;
And first and second inputs of first and second difference channels (10,20) are corresponding to each grid of the differential pair of transistors of described first and second difference channels.
2. differential amplifier as claimed in claim 1 is characterized in that, also comprises at least one amplifying circuit (30), and described amplifying circuit (30) has:
Be coupled in first output of first difference channel (10) and be coupled in first input that second of second difference channel (20) is exported;
Be coupled in second output of first difference channel (10) and be coupled in second input that first of second difference channel (20) is exported;
Be coupled in first output of differential amplifier first output; And
Be coupled in second output of differential amplifier second output.
3. as claim 1 and 2 any one described differential amplifier, it is characterized in that first and second impedances (40,60) are two variableimpedances, and the 3rd impedance (50) is a blocked impedance.
4. as claim 1 and 2 any one described differential amplifier, it is characterized in that first and second impedances (40,60) are two blocked impedances, and the 3rd impedance (50) comprises first variableimpedance (51) and second variableimpedance (52).
5. differential amplifier as claimed in claim 1 is characterized in that, described first, second and the 3rd impedance are the elements that is resistive.
6. differential amplifier as claimed in claim 5, it is characterized in that, variableimpedance comprises the element switching array that is resistive (R1), the value of variableimpedance is controlled to be the function of switching signal (C1-C5), and described function defines the configuration of the switching array of the resistance element that comprises one group of parallel connection and/or series connection.
7. differential amplifier as claimed in claim 2, it is characterized in that, also comprise two stabilizing circuits (300) that are parallel to amplifying circuit (30), in the described amplifying circuit (30) one second output with first output of first difference channel and second difference channel is connected in second of differential amplifier and exports; Another first output with second output of first difference channel and second difference channel is connected in first of differential amplifier and exports in the described amplifying circuit (30).
8. differential amplifier as claimed in claim 7 is characterized in that, each stabilizing circuit (300) comprises a plurality of impedances shunt (R that are connected in parallel to each other
A, R
B, R
C, C
A, C
B, C
C) and each self-contained commutation circuit (T
A, T
B, T
C) with control signal (M according to the input that is applied to described commutation circuit respectively
A, M
B, M
C) function and disconnect or closed at least one described a plurality of impedance along separate routes.
9. differential amplifier as claimed in claim 1, it is characterized in that, difference channel (10,20) comprises the current source (121,211) that is used for output bias, and described differential amplifier comprises that also the output (S+, S-) that is connected in differential amplifier detects and feedback control circuit (200) with the common mode of controlling described current source (121,211)
10. differential amplifier as claimed in claim 9 is characterized in that, common mode detects and feedback control circuit comprises:
Be connected in the resistor bridge (201,202) of differential amplifier output (S+, S-), described resistor bridge has the output node (204) of the voltage that transmits the average voltage that equals to appear at described output place;
Error amplifier (203), described error amplifier amplifies the voltage difference between described average voltage and the reference voltage (Vref), and sends the error signal of amplifying to current source (121,211) as control signal.
11. comprise audio frequency CD and/or DVD player and/or register as any one described differential amplifier of claim 1-10.
12. comprise " set-top box " type decoder element as any one described differential amplifier of claim 1-10.
13. comprise digital audio broadcasting (DAB), digital video networking (DVN), digital video broadcast-terrestrial (DVB-T) and/or DMB (DMB) signal coder and/or decoder as any one described differential amplifier of claim 1-10.
14. comprise audio frequency and/or video tuner as any one described differential amplifier of claim 1-10.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FRFR0503820 | 2005-04-15 | ||
| FR0503820 | 2005-04-15 | ||
| FR0503820 | 2005-04-15 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1848671A CN1848671A (en) | 2006-10-18 |
| CN1848671B true CN1848671B (en) | 2010-10-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2006100673149A Expired - Fee Related CN1848671B (en) | 2005-04-15 | 2006-03-13 | Variable-gain differential amplifier |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US7400195B2 (en) |
| EP (1) | EP1713177A1 (en) |
| CN (1) | CN1848671B (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7589559B2 (en) * | 2006-12-20 | 2009-09-15 | Silicon Image, Inc. | Current mode circuitry to modulate a common mode voltage |
| US7911275B2 (en) * | 2009-04-06 | 2011-03-22 | Infineon Technologies Ag | Constant gain control for multistage amplifiers |
| US7893746B1 (en) * | 2009-10-14 | 2011-02-22 | Texas Instruments Incorporated | High speed intra-pair de-skew circuit |
| JP5607963B2 (en) * | 2010-03-19 | 2014-10-15 | スパンション エルエルシー | Reference voltage circuit and semiconductor integrated circuit |
| CN103368514B (en) * | 2012-03-29 | 2017-10-24 | 北京普源精电科技有限公司 | A kind of measurement apparatus with variable gain amplifier |
| US9716479B2 (en) | 2013-02-08 | 2017-07-25 | Analog Devices, Inc. | Variable gain amplifier |
| US9077301B2 (en) * | 2013-05-30 | 2015-07-07 | Keithley Instruments, Inc. | Nanovolt amplifier design |
| US9209685B2 (en) * | 2013-11-25 | 2015-12-08 | Cirrus Logic, Inc. | Variable resistance device for reduced power dissipation in dimmer compatibility circuits |
| US9960947B2 (en) * | 2016-09-06 | 2018-05-01 | Mediatek Inc. | Compensation circuit of power amplifier and associated compensation method |
| US10498296B2 (en) * | 2017-03-20 | 2019-12-03 | Texas Instruments Incorporated | Differential amplifier with variable neutralization |
| CN108540102B (en) * | 2018-04-23 | 2021-09-10 | 河北工程大学 | Programmable gain amplifier |
| US11012044B2 (en) * | 2018-09-19 | 2021-05-18 | Sensata Technologies, Inc. | Amplifier with common mode detection |
| US11022629B2 (en) * | 2019-07-29 | 2021-06-01 | Analog Devices, Inc. | Low-glitch range change techniques |
| CN112033530B (en) * | 2020-08-17 | 2023-03-31 | 湖北三江航天万峰科技发展有限公司 | Gain control circuit of photoelectric detector |
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|---|---|---|---|---|
| US6462615B1 (en) * | 2001-10-01 | 2002-10-08 | International Business Machines Corporation | High speed closed loop amplifier with gain adjustment |
| CN1389980A (en) * | 2001-05-18 | 2003-01-08 | 松下电器产业株式会社 | Variable gain amplifier |
| WO2004015859A2 (en) * | 2002-08-12 | 2004-02-19 | Koninklijke Philips Electronics N.V. | Variable gain amplifier with improved control characteristics linearity |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001085958A (en) * | 1999-09-10 | 2001-03-30 | Toshiba Corp | Amplifier circuit |
| FR2818466B1 (en) * | 2000-12-15 | 2003-04-04 | St Microelectronics Sa | VARIABLE GAIN DIFFERENTIAL INPUT AND OUTPUT AMPLIFIER |
| US6646509B2 (en) * | 2002-01-23 | 2003-11-11 | Broadcom Corporation | Layout technique for matched resistors on an integrated circuit substrate |
| US6731163B2 (en) * | 2002-03-08 | 2004-05-04 | Texas Instruments Incorporated | Miller de-compensation for differential input, differential output amplifier |
| US7202741B2 (en) * | 2004-03-11 | 2007-04-10 | Gct Semiconductor, Inc. | Highly linear variable gain amplifier |
-
2006
- 2006-03-10 EP EP06290398A patent/EP1713177A1/en not_active Withdrawn
- 2006-03-13 CN CN2006100673149A patent/CN1848671B/en not_active Expired - Fee Related
- 2006-04-14 US US11/404,585 patent/US7400195B2/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1389980A (en) * | 2001-05-18 | 2003-01-08 | 松下电器产业株式会社 | Variable gain amplifier |
| US6462615B1 (en) * | 2001-10-01 | 2002-10-08 | International Business Machines Corporation | High speed closed loop amplifier with gain adjustment |
| WO2004015859A2 (en) * | 2002-08-12 | 2004-02-19 | Koninklijke Philips Electronics N.V. | Variable gain amplifier with improved control characteristics linearity |
Non-Patent Citations (1)
| Title |
|---|
| CN 1389980 A,全文. |
Also Published As
| Publication number | Publication date |
|---|---|
| US20060232336A1 (en) | 2006-10-19 |
| EP1713177A1 (en) | 2006-10-18 |
| CN1848671A (en) | 2006-10-18 |
| US7400195B2 (en) | 2008-07-15 |
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